The present invention relates generally to semiconductor packaging and, more particularly, to a semiconductor grid array package.
One type of semiconductor package is a Quad Flat Package (QFP), which is formed with a semiconductor die mounted to a lead frame. The lead frame is formed from a sheet of metal that has a die attach pad often called a flag and arms that attach the flag to a frame. Leads of the lead frame are wire bonded to electrodes of the die to provide a means of easily electrically connecting the die to circuit boards and the like. After the electrodes and leads are wire bonded, the semiconductor die and leads are encapsulated in a compound (material) such as a plastic material leaving only sections of the leads exposed. These exposed leads are cut from the frame of the lead frame (singulated) and bent for ease of connection to a circuit board. However, the QFP structure limits the number of leads, and therefore the number of package external electrical connections, that can be used for a specific package size.
Grid array packages have been developed as an alternative to QFPs. Grid array packages allow for an increased number of external electrical connections while maintaining or even decreasing the package size. Such grid array packages include Pin Grid Arrays, Ball Grid Array and Land Grid Arrays. Most conventional grid array packages are substrate based and are relatively expensive when compared with lead frame based packages. However, because of the high density of external electrical connections of lead frame based grid array packages, soldering shorts may occur between adjacent external electrical connections when they are device is soldered to a circuit board. Further, the external electrical connections of the lead frame based grid array packages are typically fabricated from a thin single sheet of conductive material, such as copper, and these connections may not be sufficiently held within the mold compound such that they can become loose. Also, the encapsulating compound may bleed (resin bleed) during molding thereby affecting yield and reliability.